HomeMy WebLinkAbout20082394.tiff PUBLIC NOTICE
t Application No: 200380523
Project: Windy Gap Firming Project
US Army Corps Applicant: Municipal Subdistrict,Northern Colorado
of Engineers Water Conservancy District
Omaha DistrictWaterway: Chimney Hollow Creek
Issue Date: August 29, 2008
REPLY TO:
Chandler J. Peter
Denver Regulatory Office
9307 South Wadsworth Blvd. 60-DAY NOTICE
Littleton, CO 80128-6901
FAX (303) 979-0602
PUBLIC NOTICE
FOR SECTION 404 PERMIT APPLICATION SUBMITTED TO
U.S. ARMY CORPS OF ENGINEERS
Notice
The District Engineer,U.S.Army Corps of Engineers,Omaha District,Nebraska(Corps)is evaluating a
Department of the Army permit application from the Municipal Subdistrict,Northern Colorado Water
Conservancy District(District),220 Water Avenue,Berthoud,Colorado 80513. Permits are issued
under Section 404 of the Clean Water Act(Section 404),which regulates the placement of dredge or fill
material in the nation's waters.
Draft EIS
The Corps has participated as a cooperating agency in the preparation of a Draft Environmental Impact
Statement(EIS)led by the Bureau of Reclamation, Great Plains Region, Eastern Colorado Area Office
(Reclamation),to analyze the direct, indirect,and cumulative effects of the proposed action. The Draft
EIS describes and discloses the estimated environmental effects of five alternatives, including the no
action alternative and four action alternatives that accomplish the purpose and need for the project.
The Draft EIS was prepared in accordance with the National Environmental Policy Act(NEPA)of
1969,as amended.Additionally,through the Corps' participation as a cooperating agency,the Draft
EIS was prepared to satisfy the Corps' regulations for NEPA implementation(33 Code of Federal
Regulations [CFR] parts 230 and 325,Appendices B and C). The Corps' Regulatory Branch will
utilize information contained in the Draft EIS and any additional information, provided either by the
applicant or through comments on the permit application, as the basis for a decision regarding the
request for a Section 404 permit.
Copies of the Draft EIS are available for review at the following locations:
• Corps of Engineers, Chatfield Reservoir Office, 9307 South Wadsworth Boulevard, Littleton,
Project: Windy Gap Finning Project Corps Ilk No: 200380523
Waterway: Chimney Hollow Creek Applicant: Municipal Subdistrict-Northern Colorado Water Conservancy District
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O / l 2008-2394
Colorado 80128
• Bureau of Reclamation,Eastern Colorado Area Office, 11056 W. County Road 18E,Loveland CO
80537
• Morgan Library,Colorado State University, 501 University Avenue, Fort Collins,Colorado 80523
• Berthoud, Berthoud Public Library, 236 Welch Avenue
• Broomfield, Mamie Eisenhower Public Library, 3 Community Park Road
• Ft. Collins, Fort Collins Public library, 201 Peterson Street
• Ft. Lupton, Ft. Lupton Public Library, 425 South Denver Avenue
• Granby, Granby Branch Library, 55 Zero Street
• Grand Lake, Juniper Library, 316 Garfield Street
• Greeley, Centennial Park Branch, Weld Library District, 2227 23'd Avenue
• Greeley, Fart Branch, Weld Library District, 1939 6l°t Avenue
• Greeley, Lincoln Park Branch, Weld Library District, 919 7th Street
• Hot Sulphur Springs, Hot Sulphur Springs Branch Library, 150 Moffat Avenue
• Kremmling, Kremmling Branch Library, 300 South 8t" Street
• Longmont, Longmont Public Library, 409 4th Avenue
• Louisville, Louisville Public Library, 95 Spruce St
• Loveland, Loveland Public Library, 300 North Adams Avenue
• Lyons, Lyons Depot Library, 5th and Broadway
Copies of the Draft EIS and related documents are available online from Reclamation's website at
littp_%_www,usbr.e.ovigp/nepa/quartcrly cfm. Paper copies of the Draft EIS may be obtained by calling
Kara Lamb of Reclamation at 970-962-4326.
Public Hearings
Reclamation will be holding two public hearings,preceded by an open house,to receive oral and
written comments on the Draft EIS. The Corps will participate in these hearings to receive
comment on the permit application and address the requirements of 33 CFR Part 327 of its
implementing regulations.Oral and/or written comments may also be presented at either or both of
the public hearings to be held at the following times and locations:
October 7,2008—Open House at 6 p.m.Public Hearing at 7 p.m. —McKee Conference Center,
2000 Boise Avenue, Loveland,CO, 80538.
October 9,2008—Open House at 5 p.m. Public Hearing 6 p.m.—Inn at Silver Creek,62927 US
Highway 40,Granby,CO, 80446.
Each public hearing will be preceded by an open house hosted by Reclamation to display project
information and allow for questions.The meeting facilities are physically accessible to people with
disabilities. People needing special assistance to attend and participate in the public hearings should
contact Ms.Kara Lamb of Reclamation at 970-9624326 as soon as possible.To allow sufficient time to
process special requests,please call no later than one week before the public hearing of interest. The
purpose of the public hearings is to provide the public with an opportunity to comment on information
presented in the Draft EIS.Oral comments may be limited to a specified period of time if deemed necessary
2
Project: Windy(lap Finning Project Corps File No: 200380523
Waterway: Chimney Hollow Creek Applicant: Municipal Subdistrict-Northern Colorado Water Conservancy District
by Reclamation to complete the hearing in an appropriate period of time. Written comments will also be
accepted at the hearings.Information regarding this proposed action is available in alternative formats
upon request.
Proposed Project,Permit Application,and Description of Work
The District is requesting authorization to place fill material into and excavate Chimney Hollow Creek
and associated wetlands in connection with the construction of the Chimney Hollow Reservoir with a
capacity of 90,000 acre-feet. The dam,reservoir and pipeline construction activities would permanently
and temporarily impact a total of 1.74 acres of wetlands(1.12 acres jurisdictional,0.62 acres non-
jurisdictional)and 1.4 acres of other waters(1.22 acres jurisdictional,0.18 acres non jurisdictional).A
full description of the proposed action is contained in the Draft EIS which should be viewed at the
previously identified locations or obtained from Reclamation for additional information.Temporary
impacts from pipeline installation (excavation and backfill)would be mitigated in place due to
restoration efforts. The applicant proposes to buy mitigation bank credits for the permanent loss of
1.06 acres of jurisdictional wetlands.The Chimney Hollow Reservoir site is located within the
secondary service area of 4 mitigation banks. Ratio of appropriate credits has yet to be determined.
Temporary impacted jurisdictional wetlands totaling 0.6 acres would be restored. The permanent loss
of 0.56 acres of non jurisdictional wetlands would be mitigated through on-site creation.The applicant
proposes this mitigation through the anticipated establishment of a fringe around the margin of the
reservoir or in flatter areas in shallow valleys associated with tributaries to the reservoir.Additionally,
areas may be graded,planted and/or seeded at the southern end of the proposed reservoir just below
the normal pool elevation of the reservoir for wetland creation.
Location
The Proposed Chimney Hollow Reservoir is located in Larimer County,Colorado in Section 33,
Township 5 North,Range 70 West and Sections 4, 5,and 9,Township 4 North,Range 70 West.
Project Purpose
Basic Project Purpose: The basic project purpose is water supply.
Overall Project Purpose: The purpose of the Windy Gap Firming Project is to deliver a firm annual
yield of approximately 30,000 AF of water from the existing Windy Gap Project to provide a portion
of the water deliveries anticipated from the original Windy Gap Project and to provide up to 3,000 AF
of storage to firm water deliveries for the Middle Park Water Conservancy District.
*********************
The Colorado Department of Public Health and Environment,WQCD-GWPS-B2,4300 Cherry Creek
Drive South, Denver,Colorado 80246-1530,will review the Proposed Project for state certification in
accordance with the provisions of Section 401 of the Clean Water Act. The certification, if issued,will
express the state's opinion that the operations undertaken by the applicant will not result in a violation of
applicable water quality standards. For further information,please contact the Colorado Water Quality
Control Division at(303)692-3500.
Reclamation is the lead federal agency to comply with the requirements of the Endangered Species Act
as allowed at 50 CFR 402.07.Additionally, Reclamation is the lead Federal agency to ensure
compliance with the requirements of the National Historic Preservation Act of 1966,as amended.The
Corps intends,after independent evaluation,to utilize Reclamation's efforts and products associated with
the EIS to satisfy its requirements for permit evaluation relative to these 2 statutes. Detailed information
concerning impacts to these resources is contained in the Draft EIS.
The decision whether to issue a permit will be based on an evaluation of the probable impacts including
cumulative impacts of the Proposed Action on the public interest. That decision will reflect the national
3
Project Windy Gap Finning Project Corps File No: 200380523
Waterway: Chimney Hollow Creek Applicant Municipal Subdistrict-Northern Colorado Water Conservancy District
concern for both protection and utilization of important resources. The benefits that reasonably may be
expected to accrue from the proposal must be balanced against the reasonably foreseeable detriments. All
factors that may be relevant to the proposal will be considered including the cumulative effects thereof;
among those are conservation,economics,aesthetics,wetlands,fish and wildlife values,flood hazards,
floodplain values, land use,navigation,shoreline erosion and accretion,recreation,water supply and
conservation,energy needs,safety,food and fiber production,mineral needs,considerations of property
ownership and, in general,the needs and welfare of the people. In addition,the evaluation of the impact
of the work on the public interest will include application of the guidelines promulgated by the
Administrator,Environmental Protection Agency,under authority of Section 404(b)of the Clean Water
Act(40 C.F.R.Part 230).
The Corps is soliciting written comments from the public;federal,state,and local agencies and officials;
Indian Tribes;and other interested parties in order to consider and evaluate the impacts of this Proposed
Action. Any comments received will be considered by the Corps to determine whether to issue,modify,
condition,or deny a permit for this proposal. To make this decision,comments are used to assess impacts
on endangered species;historic properties,water quality,general environmental effects,and other public
interest factors listed above.
4
Project: Windy Gap Firming Project Corps File No: 200380523
Waterway: Chimney Hollow Creek Applicant. Municipal Subdistrict-Northern Colorado Water Conservancy District
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United States Department of the Interior
BUREAU OF RECLAMATION TAKE minor
,c_:, Great Mains Region u+ IRRIt.A
,tsa7cW' P.O.Box 36900
wvwaum Billings,Montana 59107-6900
August 26, 2008
Dear Interested Party:
In compliance with the National Environmental Policy Act, the Bureau of Reclamation
announces the availability of the Windy Gap Firming Project Draft Environmental Impact
Statement(DEIS) for review and comment. During the next sixty days, Reclamation will be
accepting comments on the Draft EIS.
To complement the public comment process, Reclamation will host two public hearings:
• October 7, 2008, at 7 pm, McKee Conference Center, 2000 Boise Avenue, Loveland,
CO 80538, (ph. 970-669-4640)
• October 9,2008, at 7 pm, Inn at Silver Creek, 62927 US Highway 40, Granby, CO
80446, (ph. 970-887-4080)
Each public hearing will be preceded by an Open House. Additional notice of these meetings
and the open houses will be provided at a later date.
Comments may be submitted any time during the next sixty days. All comments should be
received by Reclamation by Tuesday, October 28, 2008. To submit a comment,please provide it
in writing via letter, fax, or e-mail. Comments should be sent to the attention of:
Will Tully
Bureau of Reclamation,
11056 West County Road 18E,
Loveland, CO 80537.
Fax: (970) 663-3212
Email: wtully(dgp.usbr.gov
For e-mail,please include "Windy Gap Draft EIS Comment" as the subject line.
If you received an Executive Summary and would like a complete copy of the DEIS, please visit
www.usbr.gov/gp/ecao. Copies of both documents can also be viewed at the following
locations.
• Eastern Colorado Area Office, 11056 W. County Road 18E, Loveland, CO 80537
970-962-4410
• Corps of Engineers, Chatfield Reservoir Office, 9307 South Wadsworth Blvd., Littleton, CO
80128
• Berthoud, Berthoud Public Library, 236 Welch Avenue
• Broomfield, Mamie Eisenhower Public Library, 3 Community Park Road
• Ft. Collins, Morgan Library, Colorado State University, 501 University Avenue
• Ft. Collins, Fort Collins Public Library, 201 Peterson Street
• Ft. Lupton, Ft. Lupton Public Library,425 South Denver Avenue
• Granby, Granby Branch Library, 55 Zero Street
• Grand Lake, Juniper Library, 316 Garfield Street
• Greeley, Centennial Park Branch, Weld Library District, 2227 23rd Avenue
• Greeley, Fan Branch, Weld Library District, 1939 61st Avenue
• Greeley, Lincoln Park Branch, Weld Library District, 919 7th Street
• Hot Sulphur Springs, Hot Sulphur Springs Branch Library, 150 Moffat Avenue
• Kremmling, Kremmling Branch Library, 300 South 8th Street
• Longmont, Longmont Public Library,409 4th Avenue
• Louisville, Louisville Public Library, 951 Spruce Street
• Loveland, Loveland Public Library, 300 North Adams Avenue
• Lyons, Lyons Depot Library, 5`h and Broadway
The Executive Summary provides an overview of the more detailed DEIS. With over 500 pages,
the complete DEIS with appendices presents the purpose and need of the proposed Windy Gap
Firming Project and describes the anticipated environmental effects of five alternatives.
For additional questions on the public hearings or public comment period, or to request a hard
copy of either the Executive Summary or the full Draft EIS, please contact Kara Lamb at
(970) 962-4326 or klanib(igp.usbr.gov.
Sincerely,
Michael J. Ryan
Regional Director
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RECLAMATION
Managing Water in the West
Windy Gap Firming Project
Draft Environmental Impact Statement
DES 08-30
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EXECUTIVE SUMMARY
DRAFT ENVIRONMENTAL IMPACT STATEMENT
WINDY GAP FIRMING PROJECT
INTRODUCTION
The Windy Gap Firming Project (WGFP) is a proposed water supply project that would provide more reliable
water deliveries to Front Range and West Slope communities and industries. The Municipal Subdistrict,
Northern Colorado Water Conservancy District
acting by and through the Windy Gap Firming
Project Water Activity Enterprise (Subdistrict), on + �
behalf of WGFP Participants, is seeking approval
from the U.S. Bureau of Reclamation (Reclamation)
for additional physical connections to Colorado-Big tl� . —.
Thompson (C-BT)Project facilities in order to
implement the proposed project. Reclamation's
decision on the WGFP is a major federal action
requiring preparation of an Environmental Impact
Statement(EIS). This Executive Summary
summarizes the alternatives analyzed in detail and Existing Windy Gap Reservoir, Grand County,
their anticipated environmental effects. The reader Colorado
is referred to the entire Draft EIS for a more
complete description and analysis.
Due to limitations and constraints with the existing system, the current Windy Gap facilities, which were
completed in 1985, are unable to deliver the anticipated firm yield of water. Water deliveries from the West
Slope currently are limited by storage capacity in Granby Reservoir and by the delivery capacity of the
Adams Tunnel, which delivers water from Grand Lake to the East Slope. The WGFP would add water
storage and related facilities to the existing Windy Gap operations capable of delivering a firm annual yield of
about 30,000 AF to Project Participants. The intent of the WGFP is to improve the yield from an existing
project and existing Windy Gap water rights.
Project Participants in the WGFP include municipalities,rural domestic water districts, and an industrial
water user. Project Participants on the East Slope are the City and County of Broomfield, Central Weld
County Water District, Town of Erie, City of Evans, City of Fort Lupton, City of Greeley, City of Lafayette,
Little Thompson Water District, City of Longmont, City of Louisville, City of Loveland, Platte River Power
Authority, and the Town of Superior. In addition, the project seeks to firm the water supply for the Middle
Park Water Conservancy District (MPWCD), which is a wholesale water supplier that allocates Windy Gap
water to about 67 water providers, including towns, water districts, agricultural water suppliers, consumers,
ES-1
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
and ski areas in Grand and Summit counties on the West Slope. WGFP Participants determined that a
cooperative project was the most efficient means to firm Windy Gap water deliveries rather than each entity
developing storage for its own share of Windy Gap water.
COOPERATING AGENCIES
In addition to Reclamation (the lead agency), the U.S. Army Corps of Engineers (Corps), Western Area
Power Administration (Western), and Grand County are cooperating agencies. The Corps has regulatory
authority under the Clean Water Act for actions that require the placement of dredge or fill material in a water
of the United States. Western is participating as a cooperating agency because it has jurisdiction over the
transmission line that would be relocated if Chimney Hollow Reservoir is constructed. Western would need
to acquire a new easement for the relocated line as well as construct, operate, and maintain the line. Western
also has responsibilities for marketing additional power that may be generated as a result of the WGFP.
Grand County has an interest in the project because Colorado River diversions and several alternative
reservoir sites are located in the county.
PROJECT NEED
Windy Gap Project water is currently diverted from the Colorado
River just downstream of the confluence of the Colorado and Purpose and Need
Fraser rivers into the Windy Gap Reservoir(Figure ES-1). From
The purpose of the Windy Gap Firming
the reservoir the water is pumped to Granby Reservoir for project is to deliver a firm annual yield of
storage and conveyance through C-BT Project facilities and about 30,000 AF of water from the existing
ultimate delivery to Windy Gap Project allottees on the East Windy Gap Project to meet a portion of the
Slope. MPWCD's Windy Gap water is stored in Granby water deliveries anticipated from the
Reservoir and released to replace stream diversions or ground original Windy Gap Project and to provide
water use by contract holders at various locations in Grand and up to 3,000 AF of storage to firm water
deliveries for the Middle Park Water
Summit counties. Conservancy District. Firm water
The original Windy Gap Project was estimated to deliver about deliveries from the Windy Gap Project are
48,000 acre-feet (AF) of firm annual deliveries to Windy Gap needed to meet a portion of the existing
and future demands of the Project
allottees and the MPWCD; however, Project Participants have Participants.
not been able to rely on Windy Gap water for water deliveries
for two primary reasons:
• In dry years, the Windy Gap Project has not been able to divert water because more senior water
rights upstream and downstream have a higher priority to divert water and"call out" the more junior
Windy Gap Project water right. In addition, the Windy Gap Project is required to bypass water to
maintain certain minimum streamflows downstream of the Windy Gap diversion dam.
• Granby Reservoir, a component of the C-BT Project, is currently the only storage available for Windy
Gap water prior to delivery to Participants. Water conveyed and stored for the C-BT Project has
ES-2
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Figure ES-1. Windy Gap Reservoir facilities. priority over water conveyed and stored for
/ the Windy Gap Project. Thus in wet years,
Existing Windy Gap Facilities / when the C-BT system is full,there is no
/// conveyance or storage capacity for Windy
Gap Project water. This prevents the Windy
k Gr n.y Gap Project from storing water in some wet
Willow Creek years for use in subsequent dry years.
Reservoir Willow Creek
Pump Plant Because the Windy Gap Project is unable to provide
reliable yields in both wet and dry years, the current
S ca firm yield is zero. Firm yield is typically defined as
•
Windy Gap 6aP riv;3•`.�•t
n • the amount of water that can be delivered on a
Pump Plant windy reliable basis in all years and is typically determined
o° by yield in dry years. For the Windy Gap Project,
lack of available storage space in wet years also
Wind 'Gap} affects yield.
y
Reservoir
Granby Participants in the proposed project have a need to
• Fraser Rive,
firm Windy Gap water deliveries to meet existing
• and future water demands. In 2005, WGFP
Participants had a firm water supply of about 141,000 AF and a demand of about 120,000 AF. Water demand
for East Slope Participants is projected to increase to about 251,000 AF by 2050 and shortages in firm yield at
that time would increase to more than 110,000 AF (Table ES-1). Water demand is projected to increase
17,000 AF by 2030 for Grand and Summit county water users partially served by the MPWCD. While water
conservation is an important strategy used by the Participants to improve the efficiency of water use, extend
supplies, and reduce overall demand, conservation measures will not be sufficient to meet projected water
demands. The WGFP would collectively supply about 10 percent of the projected 2050 East Slope
Participant water supply needs (Figure ES-2) and would contribute to meeting the future demands of Grand
and Summit counties. The source for about 34 percent Figure ES-2. Summary of projected 2050
of future water supplies is still unknown. It is Participant water supply sources.
anticipated that some portion of this future supply will
be realized by increased water conservation,but
additional water supplies will still be needed. Conservation
and/or New
Sources
PUBLIC AND AGENCY PARTICIPATION 34%
Reclamation provided an early and open process to
Existing
determine the scope of significant issues to be addressed = Water Supply
56%
in the Draft Environmental Impact Statement(DEIS).
Prior to initiation of the EIS process and publication of Windy Gap
the Notice of Intent in September 2003, the Subdistrict, Firming
P Project
with Reclamation participation, held two public 10%
ES-3
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Table ES-1. WGFP Participant water supply, demand, and estimated shortage.
Firm Supply Estimated Firm
Participant from All Projected 2050 Estimated 2050 Yield under the
Sources(2005) Water Demand Water Shortage Proposed
Action**
Broomfield 13,739 24,400 10,661 5,600
Central Weld County Water District 2,786 5,900 3,114 93
Erie 2,145 8,900 6,755 1,840
Evans 9,298 13,300 4,002 455
Fort Lupton 3,538 6,800 3,262 265
Greeley 43,850 78,500 34,650 2,230
Lafayette 4,534 8,600 4,066 610
Longmont 30,963 42,300 11,337 4,515
Louisville 5,063 6,900 1,837 825
Loveland 17,792 28,300 10,508 2,075
Little Thompson Water District 5,510 19,100 13,590 1,200
MPWCD NA * NA 429
Platte River Power Authority 0 5,150 5,150 5,050
Superior 1,544 3,300 1,756 1,380
TOTAL 140,762 251,450 110,688 26,567
'Grand and Summit counties project an increase in water demand of 17,000 AF by 2030,with a total build-out demand of about
32,000 AF.
"Values rounded.
information meetings in July 2003 to describe the proposed project. Following publication of the Notice of
Intent and during and after three public scoping meetings in September and October 2003, Reclamation
received input from the public, interested organizations, and agencies. An agency scoping meeting also was
held in September 2003 to gather input from federal, state, and local government agencies. Periodic
communication and meetings were held with various agencies and entities over the course of preparation of
the DEIS.
ALTERNATIVES
Following extensive screening of more than 170 different alternatives using National Environmental Policy
Act(NEPA) criteria and Clean Water Act Section 404(b)(1) guidelines, in cooperation with the Corps, five
alternatives were included for evaluation in the DEIS. The No Action alternative and four action alternatives
are described below.
• Alternative 1 (No Action): Continuation of operations under existing agreements between
Reclamation and the Subdistrict for conveyance of Windy Gap water through C-BT facilities and the
enlargement of Ralph Price Reservoir by the City of Longmont.
ES-4
r
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
• Alternative 2 (Proposed Action): Chimney Hollow Reservoir(90,000 AF)with prepositioning.
• Alternative 3: Chimney Hollow Reservoir(70,000 AF) and Jasper East Reservoir(20,000 AF).
• Alternative 4: Chimney Hollow Reservoir(70,000 AF)and Rockwell/Mueller Creek Reservoir
(20,000 AF).
• Alternative 5: Dry Creek Reservoir(60,000 AF) and RockwelUMueller Creek Reservoir
(30,000 AF).
Alternative 1 (No Action)
The No Action alternative defines what Participants would do if Reclamation does not approve a new
connection of WGFP facilities to C-BT facilities as required for the action alternatives. Under this
alternative,Participants would maximize delivery of Windy Gap water according to their demand, water
rights, availability of storage in Granby Reservoir, and existing Adams Tunnel conveyance constraints. The
City of Longmont would enlarge Ralph Price Reservoir by raising the dam and increasing storage capacity by
13,000 AF (Figure ES-3). Participants that do not have a currently defined storage option would take delivery
of Windy Gap water whenever it is available within the capacity of their existing water systems and delivery
points under the terms of the existing contract between Reclamation and the Subdistrict. Windy Gap
diversions will increase in the future regardless of whether one of the action alternatives is implemented
because of increased demand.
Figure ES-3. Ralph Price Reservoir enlargement under the No Action Alternative.
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ES-5
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Alternative 2 (Proposed Action)
The Proposed Action includes construction of a 90,000 AF "r ).
Chimney Hollow Reservoir, along with the ability to store,
or preposition, C-BT water in the new reservoir(Figure ES- s'
4). Water would be conveyed to Chimney Hollow Reservoir
via a new pipeline connection to existing East Slope C-BT •
facilities. New connections between Chimney Hollow -
Reservoir and Carter Lake would allow delivery of water to
Participants using existing infrastructure. No new West
Slope infrastructure would be needed to divert or convey
water to the East Slope.
Prepositioning would involve the use of available Adams
Tunnel capacity to deliver C-BT water into Chimney Hollow
Reservoir to occupy storage space that is not occupied by
Windy Gap water. The delivery of C-BT water from Granby Chimney Hollow Reservoir Site
Reservoir into Chimney Hollow Reservoir would create
space for Windy Gap water in Granby Reservoir. When Windy Gap water is diverted into Granby Reservoir,
the C-BT water in Chimney Hollow Reservoir would be exchanged for a like amount of Windy Gap water in
Granby Reservoir. Total allowable C-BT storage would not change and the existing C-BT diversions would
not be expanded. If operated in this manner, Chimney Hollow Reservoir would be full most of the time.
Alternative 3
Alternative 3 is a combination of a 70,000 AF Chimney Hollow Reservoir on the East Slope and a 20,000 AF
Jasper East Reservoir on the West Slope (Figure ES-4). A new, 1-mile-long pipeline would connect Jasper
East Reservoir to the existing Windy Gap pipeline that delivers water to Granby Reservoir. The Willow
Creek Pump Station, forebay, and portions of the canal and pipeline would be relocated. The availability of a
new West Slope reservoir would allow water diversions from the existing Windy Gap Reservoir to be
delivered to either Jasper East Reservoir or Granby Reservoir. Thus,when Granby Reservoir is full or the
Adams Tunnel is at capacity, Windy Gap water would be diverted and stored in Jasper East Reservoir until
there is sufficient capacity to transfer water to Chimney Hollow Reservoir.
Alternative 4
Alternative 4 is a combination of a 70,000 AF Chimney Hollow Reservoir on the East Slope and a 20,000 AF
Rockwell/Mueller Creek Reservoir(Rockwell Reservoir) on the West Slope (Figure ES-4). Deliveries to and
from Rockwell Reservoir would require a new connection to the existing Windy Gap pump station and a new
3.3-mile-long pipeline to Rockwell Reservoir. As with the Jasper East Reservoir site, the availability of a
new West Slope reservoir would allow water diversions from the existing Windy Gap Reservoir to be
delivered to either Rockwell Reservoir or Granby Reservoir. When Granby Reservoir is full or the Adams
Tunnel is at capacity, Windy Gap water would be diverted and stored in Rockwell Reservoir until there is
sufficient capacity to transfer water to Chimney Hollow Reservoir.
ES-6
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Figure ES-4. Alternative new reservoir sites.
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ES-7
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Alternative 5
Alternative 5 is a combination of a 60,000 AF Dry Creek Reservoir on the East Slope and a 30,000 AF
Rockwell Reservoir on the West Slope (Figure ES-4). Water deliveries to and from Rockwell Reservoir
would require a new pipeline and connection to the existing Windy Gap pump station. A new 3.4-mile-long
pipeline connection to C-BT facilities would convey Windy Gap water to Dry Creek Reservoir. A new 2.1-
mile-long pipeline also would be needed to deliver water from Dry Creek Reservoir to Carter Lake. As with
Alternatives 3 and 4, the availability of a new West Slope reservoir would allow water diversions from the
existing Windy Gap Reservoir to be delivered to either Rockwell Reservoir or Granby Reservoir. When
Granby Reservoir is full or the Adams Tunnel is at capacity, Windy Gap water would be diverted and stored
in Rockwell Reservoir until there is sufficient capacity to transfer water to Chimney Hollow Reservoir.
ENVIRONMENTAL EFFECTS
The WGFP would result in environmental effects to a number of resources. The effects of all of the action
alternatives related to increased water diversions would be similar because similar amounts of water would be
diverted from the Colorado River. The No Action alternative would result in similar, but smaller, effects
because Windy Gap diversions would increase in the future with a higher water demand even though the
enlargement of Ralph Price Reservoir would only increase storage for Windy Gap water by 13,000 AF. This
summary focuses on those resources with the greatest potential impacts. Effects on ground water, geology,
soils, air quality, noise, cultural resources, and visual quality are expected to be minimal and are not discussed
in this summary. Impacts to these resources are discussed in detail in the DEIS. The following sections
summarize the effects to other resources. Proposed mitigation is discussed at the end of this summary.
Surface Water Hydrology
The WGFP would result in increased diversions and reduced flows in the Colorado River below Windy Gap
Reservoir. In many years, the flows would be unchanged, but in wetter years, diversions would increase, with
a corresponding decrease in Colorado River flows. Estimated average annual flow changes from hydrologic
modeling are described below.
• Windy Gap diversions would increase about 7,000 AF per year on average from existing conditions
under the No Action alternative compared to an increase of about 9,500 AF for the Proposed Action,
and an increase of 12,000 AF for the other alternatives (Table ES-2).
• Colorado River average annual flow below Granby Reservoir would decrease about 7 percent (4,000
AF)under the No Action alternative, 15 percent (9,000 AF)under the Proposed Action, and 12 to 13
percent for the other alternatives as a result of the availability of additional Windy Gap storage and
fewer reservoir spills (Table ES-2).
• Colorado River average annual flow below the Windy Gap diversion would decrease by 8 percent
(12,000 AF)under the No Action alternative compared to a 14 percent (21,000 AF) decrease for the
action alternatives (Table ES-2). The majority of the reductions in flow would occur between May
and August (Figure ES-5)with average monthly flow reductions up to 20 percent for the No Action
alternative, 23 percent for the Proposed Action, and 28 percent for Alternatives 3 to 5. The average
monthly percent flow reduction would be greater in wet years. In dry years, there would be no
change in flow from existing conditions.
ES-8
r
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Table ES-2. Average annual changes in Colorado River flow and diversions by alternative.
Colorado River Windy Gap Colorado River Colorado River
below Granby Diversions below Windy Gap below Kremmling
Alternative Reservoir g
AF % AF % AF % AF
Existing Conditions 59,385 36,532 — 151,358 701,801
Alt 1—No Action 55,345 -7 43,573 +19 138,914 -8 689,357 -2
Alt —Proposed Action 50,220 -15 46,084 +26 130,075 -14 680,512 -3
Alt 3 52,071 -12 48,052 +32 130,370 -14 680,807 -3
Alt 4 52,091 -12 47,997 +31 130,453 -14 680,890 -3
Alt 5 51,903 -13 48,483 +33 129,681 -14 680,118 -3
• Below Kremmling and the confluence with the Blue River, Colorado River average annual
streamflow reductions would be about 2 percent (12,000 AF)under the No Action Alternative and 3
percent(21,000 AF) for the action alternatives (Table ES-2).
• Average annual Willow Creek streamflow below Willow Creek Reservoir would decrease by 7
percent(1,400 AF)under the No Action alternative, 14 percent(2,600 AF)for the Proposed Action,
and 12 percent (2,200 AF) for the other alternatives due to changes in Willow Creek Feeder Canal
deliveries to Granby Reservoir.
• Big Thompson River flows below Lake Estes would increase about 1 percent(450 AF) on average
under the No Action alternative compared to a 5 percent increase (3,200 AF) for the Proposed Action,
Figure ES-5. Average daily flow in the Colorado River below Windy Gap Reservoir by alternative.
1,200
—Existing Gond
—No Action
1,000 —Proposed Action
Alt 3
Alt 4
— Aft 6
800 ___... . __- 1,+.♦-\ _.. __
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LL 600co
at
400
200 �.
0
Apr May Jun Jul Aug Sep Oct Nov
Beginning of Month
ES-9
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
and less than a 2 percent increase (1,000 AF)for the other alternatives as a result of the additional
Windy Gap water imports and lower diversions for power generation in the C-BT system.
• Streamflow below Participant wastewater treatment plants (WWTPs) would increase from the
discharge of Windy Gap return flows to the Big Thompson River, St. Vrain Creek, Big Dry Creek,
and Coal Creek.
• Water levels in Grand Lake or Shadow Mountain Reservoir would not change under any of the
alternatives.
• Granby Reservoir average monthly water levels would decrease from 2 to 3 feet under the No Action
alternative, 5 to 8 feet under the Proposed Action, and 3 to 4 feet under the other alternatives (Figure
ES-6). A series of dry years could lower water levels up to 23 feet under the Proposed Action.
• Water levels in Carter Lake would decrease less than 1 foot under all of the alternatives.
• Average monthly water levels in Horsetooth Reservoir would not change under the No Action
alternative, would decrease 2 to 6 feet under the Proposed Action, and would decrease 0 to 2 feet
under the other alternatives.
• Windy Gap firm yield would increase from zero under existing conditions to about 26,000 AF under
the Proposed Action and alternatives (Table ES-3). Firm yield under the No Action alternative would
be about 1,200 AF and would not meet the project purpose and need.
Figure ES-6. Granby Reservoir estimated average monthly surface elevation by alternative.
III 8,275 --
8,270
•
8,265
•
8260 ---
- 8,255 •
g 8,250
•
m 8245 •
•
8,240 Existing Cond
Alt 1-No Action
8,235 ---- ----- — — ,.—Alt 2-Chimney Hollow
—Alt 3-Chimney Hollow w/Jasper East
Alt 4-Chimney Hollow w/Rockwell Creek
8,230 - - - Alt 5-Dry Creek w/Rockwell Creek
Results for Alternatives 3.4 and 5 are similar,so lines may overlap-
8,225
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Month
•
ES-10
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Stream Morphology and Floodplains Table ES-3. Windy Gap Firming Project firm
Stream morphology refers to the form and structure of a yield.
stream, including its channel, banks, floodplain and Condition/Alternative Firm Yield(AF)
drainage area, which could be altered as a result of Existing Conditions 0
changes in flow. The upper Colorado River is a Alt. 1-No Action 1,229
morphologically stable stream. The changes in flow Alt.2-Proposed Action 26,559
expected from the WGFP are not expected to cause Alt. 3 25,849
measurable changes to stream morphology or to
AlL 4 25,849
sediment transport and deposition in the Colorado River
Alt. 5 26,629
below Windy Gap Reservoir. -
• Under all alternatives, the 2-year peak discharge on the Colorado River at the Hot Sulphur Springs
gage below the Windy Gap diversion would be exceeded about 3 percent of the time, or about 1
percent less frequently than under existing conditions. High volume channel maintenance flows
would also experience a slight decrease in frequency. The projected reduction in the frequency of
peak discharges and channel maintenance flows is unlikely to significantly affect stream morphology
or change sediment transport or deposition.
• Flushing flows in the Colorado River equal to or greater than 450 cfs, which occur about 45 days per
year on average under existing conditions, would decrease to 38 days per year under the No Action
alternative, 36 days under the Proposed Action, and 35 days under the other alternatives. The
reduction in the frequency of flushing flows would remain adequate to transport sediment and prevent
dcposition.
• Increased flows in East Slope streams below the Participants WWTPs would have minimal effect on
stream morphology.
• The potential for flooding along the Colorado River and Willow Creek would decrease and the
potential for flooding along East Slope streams below the Participants WWTPs would increase
slightly.
Surface Water Quality
Water quality impacts from WGFP include changes in the Colorado River below Granby Reservoir, in
Willow Creek below Willow Creek Reservoir, and in several East Slope streams, including the Big
Thompson River, St. Vrain Creek, North St. Vrain Creek, Coal Creek, Big Dry Creek, and the Cache la
Poudre River. Potential effects to water quality were also evaluated in the Three Lakes system (Granby
Reservoir, Shadow Mountain Reservoir, and Grand Lake), Carter Lake, and Horsetooth Reservoir, as well as
the predicted water quality for new reservoirs. Stream and reservoir water quality models were used to
estimate the following water quality effects.
• Under average flow conditions for a typical late July day below Windy Gap Reservoir, temperatures
in the Colorado River are predicted to increase 0.5°C under the No Action alternative, 0.6°C for the
Proposed Action, and 0.7°C to 0.8°C for the other alternatives. This would increase the potential for
exceedance of the maximum weekly average temperature standard (18.2°C) for all alternatives.
• When Windy Gap diversions reduce Colorado River flow to the 90 cfs minimum flow in late July
(which occurs infrequently), temperatures are predicted to increase about 4°C for all alternatives
ES-11
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
(Figure ES-7). This would increase the potential for exceedance of the maximum weekly average
temperature standard under all alternatives.
Figure ES-7. Colorado River predicted average daily stream temperatures for July 25 assuming
diversion to the 90 cfs minimum instream flow below Windy Gap Reservoir.
20
18
16 Granby _
Reservoir t u 14 -- - Muddy
w 12 1 Troublesome Creek and
p I HAP Creek Blue River
m 10
Reservoir - Williams Fork
m
a 8 - -- - II—Existing Conditions-
ii 6 1 —No Action
Willow
Creek —Proposed Action
4 --_—.-_ ____Fraser River _ _-
—Aa3
2 I—Aa4
—AIt5
0 r i
0 5 10 15 20 25 30 35 40 45
River Mile(mi)
• Ammonia and inorganic phosphorus concentrations in the Colorado River are predicted to increase
and dissolved oxygen (DO) concentrations decrease under all alternatives. Water quality standards
would not be exceeded under average flow conditions,but when Windy Gap diversions reduce flow
to the 90 cfs minimum flow, the DO concentrations is predicted to be less than the spawning standard
for a few miles upstream of the Williams Fork.
• Ammonia and some metal concentrations in Willow Creek would increase slightly for all alternatives,
but water quality standards arc not expected to be exceeded.
• Total phosphorus concentrations in Granby Reservoir are predicted to increase under all alternatives
and total nitrogen concentrations would increase under the No Action and Proposed Action
alternatives (Table ES-4). Alternatives 3 to 5 would have lower nitrogen levels due to the effects of
storage in a West Slope Reservoir prior to delivery to Granby Reservoir. Chlorophyll a
concentrations (algae) are predicted to increase under the Proposed Action, but there would be no
Table ES-4. Granby Reservoir predicted water quality changes by alternative compared to existing
conditions.
Parameter Alternative 1 Alternative 2 Alternative 3 Alternative 4 Alternative 5
No Action Proposed Action
Total phosphorus(µg/L) +6.3% +12.7% +4.0% +3.2% +1.6%
Total nitrogen(µg/L) +0.3% +0.7% -2.1% -2.8% -3.5%
Chlorophyll a(µg/L) No Change +2.4% No Change No Change No Change
Peak chlorophyll a(µg/L) No Change -1.5% No Change No Change No Change
Secchi-disk depth(m) No Change No Change No Change No Change No Change
Trophic state No Change No Change No Change No Change No Change
Minimum DO(mg/L) -2.2% -4.4% No Change No Change No Change
TSS(mg/L) No Change +4.3% +4.3% +4.3% +4.3%
ES-12
r
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
change in water clarity as measured by the Secchi-disk depth for any of the alternatives.
• All alternatives would increase phosphorus concentrations in Shadow Mountain Reservoir; total
nitrogen would increase in Alternatives I to 3 and decrease in Alternatives 4 and 5 (Table ES-5).
Chlorophyll a concentrations would increase in Alternatives 1 to 3. Water clarity would not change
in any alternative. Dissolved oxygen would decrease under the Proposed Action and not change in
other alternatives.
Table ES-5. Shadow Mountain Reservoir predicted water quality changes by alternative compared to
existing conditions. _
Alternative 1 Alternative 2 Alternative 3 Alternative 4 Alternative 5
Parameter No Action Proposed Action
Total phosphorus(µg/L)
+5.6% +11.3% +8.1% +4.8% +3.2%
Total nitrogen(pg/L) +1.1% +1.8% +0.4% -0.7% -1.1%
Chlorophyll a(µg/L) +1.8% +1.8°% +1.8% No Change No Change
Peak chlorophyll a(µg/L) +3.4% +6.8% +1.1% No Change -1.1%
Secchi-disk depth(m) No Change No Change No Change No Change No Change
Trophic state No Change No Change No Change No Change No Change
Minimum DO(mg/L) No Change -1.4% No Change No Change No Change
+5.0% +5.0% +5.0%
TSS(mg/L) +5.0% +5.0% —
• In Grand Lake, total phosphorus concentrations are expected to increase under all alternatives (Table
ES-6). Total nitrogen is expected to increase under the No Action and Proposed Action alternatives.
Chlorophyll a concentrations would increase under all alternatives and Secchi-disk depth would
decrease under all alternatives, except Alternative 5. Dissolved oxygen concentrations would
decrease under all alternatives.
Table ES-6. Grand Lake predicted water quality changes by alternative compared to existing
conditions.
Alternative 1 Alternative 2 Alternative 3 Alternative 4 Alternative 5
Parameter No Action Proposed Action
Total phosphorus(pg/L) +6.0% +12.0% +6.0% +6.0% +4.8°%
Total nitrogen(µg/L) +0.4% +1.6% -0.4% -0.4% -0.8%
Chlorophyll a(µg/L)
+4.2% +6.1% +4.2% +2.0% +2.0%
Peak chlorophyll a(pg/L) +4.1% +5.4% +1.4% +1.4% No Change
Secchi-disk depth(m) -3.8% -3.8% -3.8% -3.8°% No Change
Trophic state No Change No Change No Change No Change No Change
Minimum DO(mg/L)
-11.1% -7.4% -5.6% -5.6% -5.6%
+5.6°% +5.6% +5.6% No Change
TSS(mg/L) No Change __ —
• No additional water quality standards would be exceeded at the Three Lakes,but temperature and DO
concentrations would continue to exceed state standards in Granby Reservoir. Lower DO levels
would contribute to continued exceedance of the manganese standard in the Three Lakes.
ES-13
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
• Ammonia concentrations in St. Vrain Creek, Big Dry Creek, and Coal Creek would increase under all
of the alternatives. The potential for exceedance of the water quality standard is possible for some
locations.
• In Carter Lake and Horsetooth Reservoir, total phosphorus, total nitrogen, and chlorophyll a
concentrations would increase, and DO concentrations would decrease. Lower DO concentrations in
Horsetooth Reservoir would contribute to continued exceedance of the manganese standard.
Aquatic Resources
The assessment of effects to fish habitat along the Colorado River was modeled following the concepts of the
Instream Flow Incremental Methodology (IFIM). This approach combines stream hydraulics, habitat use
criteria, and hydrology to predict fish habitat as a function of streamflow. Fish community and fish
populations were assessed based on changes in physical habitat, as well as projected water quality changes
within those systems in rivers and reservoirs. The changes were compared to the existing conditions to
determine if there would be factors that affect fish populations at the acute or chronic level. Major effects are
summarized below:
• The amount and frequency of available fish habitat in the Colorado River would decrease under all
alternatives from reductions in streamflow. The greatest change would occur under the action
alternatives, where up to a 24 percent decrease in adult rainbow trout habitat just upstream of the
Williams Fork confluence would occur in 4 out of 10 years. Under the No Action alternative, the
maximum decrease in habitat at this location would be 9 percent in 3 out of 10 years. Effects to
juvenile rainbow trout and juvenile and adult brown trout would be less under all alternatives. The
greatest reductions in fish habitat would occur during high runoff for a few months in the early spring
and summer when Windy Gap diversions occur. A decrease in habitat at this time would have less
impact than changes in flow during other times of the year when Windy Gap does not affect flows
and less habitat is available.
• No adverse impacts to spring spawning rainbow trout or fall spawning brown trout are predicted for
any of the alternatives.
• The potential for exceedance of the aquatic life temperature standard would increase at lower flows in
the summer, but measurable impacts to fish populations are not expected because flow reductions in
July and August would be infrequent.
• The amount and frequency of available fish habitat in Willow Creek would decrease from reduced
summer flows.
• Lower water levels and changes in water quality in Granby Reservoir, Carter Lake, and Horsetooth
Reservoir are unlikely to impact fish.
• Increased East Slope streamflows would slightly enhance fish habitat in the Big Thompson River, St.
Vrain Creek, Big Dry Creek, and Coal Creek.
• Flow changes in North St. Vrain Creek under the No Action alternative would affect fish habitat both
positively and negatively depending on storage and release from Ralph Price Reservoir.
Vegetation and Wetlands
Permanent effects to vegetation and wetland resources would occur in areas that would be inundated by a
reservoir or located within the footprint of dams, roads, relocated transmission line, or other facilities.
ES-14
n
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Temporary effects to vegetation and wetlands from construction of pipelines, staging areas, and other short-
term disturbances would be revegetated following construction.
• The enlargement of Ralph Price Reservoir under the No Action alternative would result in a loss of
about 77 acres of forest vegetation. Construction of Chimney Hollow Reservoir would permanently
impact about 790 acres of shrublands, grasslands, and forest vegetation. The other alternatives would
impact about 1,000 to 1,100 acres of mixed vegetation types.
• All of the alternatives would result in permanent and temporary impacts to wetlands and other waters
(Table ES-7). Of the action alternatives, the Proposed Action would have the least impact to
wetlands and waters.
Table ES-7. Summary of effects to wetlands and other waters by alternative.
Alternative 1 Alternative 2 Alternative 3 Alternative 4` Alternative 5
Wetlands and No Action Proposed Action
Other Waters Acres
Permanent 0.4 2.9 30.3 9.4-20.0 15.7-28.3
Temporary — 0.2 5.2 3.9-6.9 4.3-7.3
TOTAL 0.4 3.1 35.5 13.3 -26.9 20.0-35.6
'The range in wetland impacts is due to uncertainty about the wetlands present at the Rockwell/Mueller Creek Reservoir
site. Access to this site was for field survey was denied by the landowners.
Wildlife
The potential effects on wildlife resources were assessed using information on known populations or suitable
habitat. Permanent impacts to wildlife habitat could occur in areas that would be inundated or permanently
disturbed by project features such as the dam, access roads, and pump stations. Temporary impacts to habitat
from pipelines and staging areas would be reclaimed following construction. Effects to waterbirds and
aquatic and riverine mammals from changes in hydrology were based on potential effects to riparian
vegetation.
• Enlargement of Ralph Price Reservoir would result in the loss of 77 acres of elk and mule deer winter
range and habitat for other terrestrial wildlife species.
• Construction of Chimney Hollow Reservoir under the Proposed Action would result in the loss of 810
acres of elk winter range, mule deer winter range and concentration area, and black bear foraging
area. A slightly smaller Chimney Hollow Reservoir under Alternatives 3 and 4 would impact similar
habitats on about 675 acres. Habitat for migratory birds, northern leopard frog, common garter snake,
and other species would be impacted at Chimney Hollow Reservoir.
• Construction of Jasper East Reservoir would impact about 480 acres of moose and mule deer summer
range and 24 acres of elk winter range. Elk movement in the area could shift as a result of the new
reservoir.
• Construction of Rockwell Reservoir would affect about 312 acres of summer range for moose and
mule deer and 73 acres of elk winter range. About 300 acres of greater sage grouse habitat would be
lost.
ES-15
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
• Construction of Dry Creek Reservoir would result in the loss of about 650 acres of elk and mule deer
winter range.
Threatened and Endangered Species
Federally threatened and endangered species are protected under the Endangered Species Act. Potential direct
and indirect effects to threatened or endangered species were evaluated for each alternative.
• All of the alternatives would result in depletions that affect Colorado River endangered fish
downstream of the Windy Gap diversion. Future Windy Gap depletions in all alternatives are
expected to be covered by the Recovery Plan for Upper Colorado River endangered fish. As a result,
the WGFP would have no effect to the endangered fish species if the steps outlined in the Recovery
Plan and Programmatic Biological Opinion are followed.
• Construction of Rockwell Reservoir would result in the loss of less than 10 acres of potential lynx
habitat.
Land Use and Ownership
Potential effects to existing land ownership were evaluated by overlaying proposed project facilities for each
alternative on land ownership maps. Potential conflicts with local land use regulations were also evaluated
for each of the alternative reservoir sites. Predicted construction traffic volumes and visitor estimates were
used to evaluate short and long-term effects to local traffic.
• Enlargement of Ralph Price Reservoir would occur entirely on City of Longmont property. Traffic
would increase on U.S. 36 and County Road 80 during construction.
• Construction of Chimney Hollow Reservoir would require acquisition or easements on private and
Reclamation land, and relocation of 3.8 miles of Western's transmission line. Traffic would increase
on County Road 18E and County Road 31 during construction. Recreation traffic on County Road
18E would also increase when the reservoir is complete.
• Construction of Jasper East Reservoir would require acquisition of Reclamation managed land and
relocation of the Willow Creek Pump station and a portion of the canal (facilities that are part of the
C-BT Project). County Road 40 to Willow Creek would need to be relocated and a right-of-way
through private land would have to be obtained.
• Construction of Rockwell Reservoir would require acquisition of private land, including four
residences. Bureau of Land Management property would also be affected and realignment of County
Road 57 would be required. Traffic would increase on these county roads and U.S. 40 during
construction.
• Private, state, and Reclamation managed property would be affected by construction of Dry Creek
Reservoir. Three private residences and a llama operation would be impacted. Traffic on County
Road 31 would increase during construction.
• No elements associated with the construction of alternative reservoirs and facilities were identified
that would directly conflict with local land use plans or other regulations. The review process in
Larimer, Grand, and Boulder Counties would further evaluate the effects of the actions and any
conditions for approval.
ES-16
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Recreation
Potential recreation effects were based primarily on changes in hydrologic conditions at reservoirs and
streams in the study area. Changes in preferred flows for rafting and kayaking in the Colorado River were
used to evaluate the effect on river recreation.
Potential effects to rafting and kayaking on the Colorado River were evaluated for Byers Canyon below Hot
Sulphur Springs, and in the Big Gore Canyon and Pumphouse reaches of the Colorado River below
Kremmling. Daily hydrologic data from 1950 to 1996 were used to estimate the change in the number of
days when preferred rafting and kayaking flows would occur in these reaches of the river.
• There would be no change in the number of days that flows exceed the minimum kayaking flows in
Byers Canyon in 29 years of the 47-year study period. In the remaining 18 years, there would be an
estimated average decrease of 8 days per year with flows less than the preferred kayaking minimum
of 400 cfs under the No Action alternative and an estimated average of 12 fewer days per year for the
action alternatives.
• For Big Gore Canyon, there would be no change from existing conditions in the number of days that
preferred rafting flows of 850 to 1,250 cfs occur for any of the alternatives in 37 years of the 47-year
study period. Preferred rafting flows in Gore Canyon would occur about 24 days less under the No
Action alternative compared to existing conditions over the 47-year study period. Under the
Proposed Action, preferred rafting flows would occur about 23 days less than existing conditions over
the 47 years. On average, this would be about 2.3 days per year with fewer preferred rafting flows
during the 10 years when flows fall outside of the preferred range. The greatest decrease in the
number of days with preferred flows for rafting in the driest year would be 11 days under all of the
alternatives. Average monthly flows and preferred flows for rafting are shown in Figure ES-8.
• The number of days preferred kayaking flows between 1,100 and 2,200 cfs occur in Big Gore Canyon
and the Pumphouse reach would not change in 32 years of the 47-year study period for any of the
alternatives. Over the 47-year study period, there would be about 1 more day of preferred kayaking
flows under the No Action alternative and Alternative 4 compared to existing conditions. On average
during the 15 years, when preferred flows are not met, there would be about 1 less day per year in the
preferred rafting flow range under Alternatives 2, 3, and 5. The greatest change in the number of
days with preferred flows for kayaking in the driest year would be 15 days fewer under all of the
alternatives, with an increase of up to 7 days with preferred kayaking flows under the No Action
alternative and 6 more days under the Proposed Action.
• There would be no change from existing conditions in the number of days when preferred rafting and
kayaking flows in the Pumphouse reach are between 2,000 to 3,000 cfs in 28 years of the 47-year
study period under all alternatives. Over the 47-year period, there would be 6 more days of preferred
flows under the No Action alternative and 20 fewer days under the Proposed Action. On average
during the 19 years where flow changes occur, there would be about 1 less day per year in the
preferred rafting flow range under all of the alternatives The greatest decrease in the preferred flow
range in a single year would be 17 days fewer under all of the action alternatives except Alternative 5,
which would have 5 fewer days. The greatest increase in the number of days of preferred flows in a
year would be 11 days under the No Action alternative compared to an increase of 3 days under the
Proposed Action and 4 to 8 days under the other alternatives.
ES-17
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Figure ES-8. Average monthly streamflows on the Colorado River through Big
Gore Canyon for rafting.
3000 - -
2500
2000 - Existing Conditions
e•Alt 1- No Action
Alt 2- Proposed
11500 - O Alt 3 -5
° Preferred Maximum Flow
1000 - Preferred Minimum Flow
Preferred Flow
500
0
May Jun Jul Aug Sep
Month
• No measurable effect to angler user days on the Colorado River or associated economic effects were
identified for any of the alternatives.
• Access to Granby Reservoir boat ramps at Arapaho Bay, Stillwater, and Sunset would diminish in
some months, primarily under the Proposed Action due to lower water levels.
• Kayaking opportunities in North St. Vrain Creek would be reduced in July under the No Action
alternative.
• Access to the South Bay-South boat ramp in Horsetooth Reservoir would be impacted under the
Proposed Action in September and by all alternatives in dry years.
• Chimney Hollow Reservoir would provide nonmotorized boating, fishing, and hiking opportunities
under Larimer County management, with 50,000 visitors estimated annually.
• No managing agency has been identified for other potential new reservoirs, but recreation
development is possible if a managing entity is found.
Socioeconomics
Socioeconomic effects evaluated include the cost of alternatives, impact of construction and operation on
employment and spending, and the effects of hydrologic changes to recreation resources, such as boating and
fishing.
ES-18
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
Table ES-8. Project, direct labor, and operation and maintenance costs by alternative.
Total Project Costs r Direct Labor Annual O&M Costs
Alternative
Millions of 2005 dollars
Alternative 1 —No Action S31 $8 No change
Alternative 2—Proposed Action 5223 547 $0.79
Alternative 3 $240 $49 $1.37
Alternative 4 5252 $52 $1.73
Alternative 5 $288 560 52.24
*Cost for Chimney Hollow Reservoir in 2007 dollars has increased 17 percent to$261 million.
• Enlargement of Ralph Price Reservoir under the No Action alternative would cost about $31 million
(Table ES-8). The cost of the action alternatives in 2005 dollars, ranges from 5223 million for the
Proposed Action to $288 million for Alternative 5.
• All of the alternatives would increase local and regional employment and construction-related
spending.
• The alternatives would generate additional hydropower revenues ranging from$850,000 for the No
Action alternative to 51.4 million for Alternative 5. Western would use this energy to fill existing
contracts entered into following original construction of the Windy Gap Project.
• Hydrologic changes that reduce or increase the number of days that preferred flows for boating in the
Colorado River occur, could impact recreation-associated spending. Assuming a decrease in the
number of days of preferred flows results in a total loss in recreation user days, the annualized cost or
benefit to recreational boating based on changes in flow preferences over the 47-year study period is
shown in Table ES-9.
Table ES-9. Annualized cost(-) or benefit(+)from recreational boating on the Colorado River by
alternative.
Byers Canyon Big Gore Canyon Pumphouse
Alternative (rafting and kayaking)(kayaking) Y g) Kayaking Rafting
Alternative 1 —No Action -$416 -$1,458 +5349 +$2,097
Alternative 2—Proposed Action -$416 -$1,393 -$1,397 -56,989
Alternative 3 -$416 -S1,393 -51,397 -$7,339
Alternative 4 -$416 -$1,151 -$1,048 -S9,437
Alternative5 -5416 -S1,635 -$349 -$1,747
• The economic effect for the worst-case individual year(based on the 47-year study period) when
preferred flows would not be available, would result in a loss of about 429 visitor days for
commercial rafting in Big Gore Canyon with a value of about S31,000. A decrease in the number of
days with preferred kayaking flows in Big Gore Canyon and Pumphouse would result in the loss of
about 3,375 visitor days with a value of about S246,000. A reduction in preferred flows for rafting in
Pumphouse would result in a loss of 3,875 user days with a value of$279,000. This analysis is a
"worst case" scenario, which assumes no boating when flows are outside of the preferred range.
ES-19
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
• Some years would have an increase in boating days within the preferred ranges and would result in
675 to 2,475 additional visitor days with a value of 549,275 to $180,675.
CUMULATIVE EFFECTS
Several reasonably foreseeable actions are anticipated to occur regardless of the implementation of any of the
action alternatives or the No Action alternative. Reasonably foreseeable future actions, when combined with
past and present actions and the alternatives evaluated in this EIS, may result in cumulative effects.
Reasonably foreseeable effects were classified as either water-based or land-based actions that might have
effects overlapping those of the WGFP.
Water-based Reasonably Foreseeable Actions
• Denver Water Moffat Collection System Project
• Increased water use from population growth in Grand and Summit counties
• Reduction of Xcel Energy's Shoshone Power Plant call
• Changes in releases from Williams Fork and Wolford Mountain reservoirs to meet flow
recommendations (10,825 AF of water) for endangered fish
• Increase in Wolford Mountain Reservoir contract demand
• Expiration of Denver Water's contract with Big Lake Ditch in 2013
• Climatic change and global warming (not quantitatively assessed)
• Mountain pine beetle killed trees (not quantitatively assessed)
Land-based Reasonably Foreseeable Actions
• Various residential developments near new reservoir sites
• Western's replacement of the transmission line from the Granby Pumping Plant to the Windy Gap
substation
• Larimer County open space development near Chimney Hollow Reservoir
Cumulative Resource Effects
Future implementation of water-based reasonably foreseeable actions would result in changes in the amount
and timing of Colorado River streamflows. In general, less water would be available for diversion by the
WGFP. Firm yield for the Proposed Action would be about 2,500 AF less than under the direct effect model
run (24,000 AF). The hydrologic changes associated with the WGFP would be slightly less than those
described for direct effects because of the lower water diversions. Water quality in the Colorado River from
lower overall flows and increased wastewater discharges upstream of Windy Gap Reservoir would result in
higher ammonia concentrations and possibly lower inorganic phosphorus levels with assumed improvements
in wastewater treatment. Water quality in the Three Lakes, Carter Lake, and Horsetooth Reservoir would be
similar to that under direct effects. Less fish habitat would be available in the Colorado River from the
cumulative decrease in streamflows. Preferred recreational boating flows in the Big Gore Canyon and
Pumphouse reaches of the Colorado River would occur less frequently, primarily because of lower Blue River
flows from increased Denver Water demands. The economic effects of reduced preferred flows for boating
also would be greater than under direct effects. Other resource effects would be similar to those described for
direct effects.
ES-20
r
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
MITIGATION
The Subdistrict has identified potential mitigation measures to reduce the impacts associated with
implementation of the proposed WGFP. Most of these mitigation measures are applicable to all alternatives,
but several are specific to the Proposed Action as noted. The inclusion of these mitigation measures does not
imply that all measures listed will be implemented. Several mitigation measures under consideration will
require additional hydrologic and water quality modeling, as well as coordination with cooperating agencies
and other entities to accurately evaluate their value and effectiveness. These additional evaluations will be
conducted between release of the DEIS and preparation of the Final EIS. In addition, it is anticipated that
other mitigation strategies may be identified from the comments received on the DEIS. The Final EIS will
include the mitigation measures that will be implemented for the selected alternative.
• To reduce potential drawdowns in Granby Reservoir under the Proposed Action, it may be possible to
modify prepositioning operations to deliver less C-BT or Windy Gap water to Chimney Hollow
Reservoir during dry years. Additional hydrologic evaluations would be conducted to determine if
changes in the timing of water deliveries to the East Slope can reduce impacts to Granby Reservoir
while still meeting the purpose and need for the project.
• The Subdistrict will commit to continued participation and funding of the ongoing Nutrient Studies,
with participation and collaboration by Reclamation, Northern Water and Grand County, to better
understand water quality issues in the Three Lakes system and provide guidance for future
management decisions
• The Subdistrict will work with Grand County, the Colorado Division of Wildlife(CDOW), and others
to determine if increasing bypass flows in the Colorado River from the existing minimum flow of 90
cfs to 135 cfs while Windy Gap is pumping during July and August would result in temperature
reductions downstream of Windy Gap that would measurably benefit the trout fishery. If studies
indicate that increased bypass flows would be effective, the Subdistrict would consider increasing
required bypass flows under certain water supply conditions.
• A variety of best management practices will be implemented during and following construction to
reduce erosion, protect water quality, suppress dust and noise, revegetate disturbed areas, and protect
or avoid important wildlife habitat.
• All permanent wetland impacts will be replaced by purchasing credit in a wetland bank and on-site
wetland creation.
• The Subdistrict will participate in the Recovery Program for endangered Colorado River fish.
• Opportunities for improvements to aquatic life habitat in the Colorado River and mitigation of
impacts to fish will be coordinated with the CDOW, Grand County and other responsible agencies.
• Per an agreement with Larimer County Parks and Open Lands, Chimney Hollow Reservoir will be
managed as open space. A plan for habitat restoration and enhancement, including development of a
sport fishery at Chimney Hollow Reservoir, would be developed with Larimer County and CDOW.
Similar agreements would be sought for other reservoir sites.
• The Subdistrict will curtail Colorado River diversions during the annual Big Gore Race, typically
held the third week in August, if flows at the Kremmling gage arc below 2,200 cfs.
ES-21
EXECUTIVE SUMMARY
WINDY GAP FIRMING PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT
• Additional evaluation and mitigation for adverse effects to eligible cultural resources will be
conducted in coordination with Reclamation and the State Historic Preservation Officer.
• Additional specific mitigation measures are discussed in the DEIS.
WHAT'S NEXT?
Public hearings will be held after release of the DEIS. The time, date, and location of future opportunities for
comments will be mailed to those on the Reclamation's mailing list and will be posted on Reclamation's
website. Public notice on the availability of the DEIS also will be posted in local newspapers and copies of
the DEIS will be placed in local libraries. Reclamation welcomes all comments during the 60-day comment
period. Written and oral comments may also be made at the public hearings. Comments on the DEIS can be
sent by:
Mail: Will Tully, Bureau of Reclamation
11056 West County Rd. 18E
Loveland, CO 80537
Fax: Will Tully, 970-663-3212
E-mail: wtully@gp.usbr.gov (with Windy Gap Draft MS Comment as the subject line)
Copies of the DEIS and related documents arc available online from Reclamation's website at:
http://www.usbr.gov/gp/nepa/quarterly.cfm#ecao
Paper copies of the DEIS may be obtained by calling Kara Lamb at 970-962-4326.
ES-22
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